Data storage systems are arrangements of hardware and software that include one or more storage processors coupled to arrays of non-volatile storage devices, such as magnetic disk drives, electronic flash drives, and/or optical drives, for example. The storage processors service storage requests, arriving from host machines (“hosts”), which specify files or other data elements to be written, read, created, or deleted, for example. Software running on the storage processors manages incoming storage requests and performs various data processing tasks to organize and secure the data elements stored on the non-volatile storage devices.
Data storage systems commonly employ snapshot-shipping replication for protecting the data they store. A well-known snapshot-shipping solution is the Celerra Replicator™ V2, which is available from EMC Corporation of Hopkinton, Mass. Replicator V2 operates by taking snaps (i.e., point-in-time versions) of data objects at a source data storage system, identifying differences between current snaps and previous snaps, and sending the differences to a destination data storage system. The destination receives the differences and applies them to corresponding objects maintained locally, to update the objects with changes that mirror those made to the respective objects at the source. The objects at the destination may thus be regarded as replicas of the objects at the source, and the role of serving the objects to hosts may failover from source to destination in the event of a loss of service at the source.